Control valves for well tools

ABSTRACT

The invention disclosed herein is directed to new and improved control valves which are particularly adapted for selectively operating pressure-actuated well tools. In particular, different embodiments are disclosed of high-pressure control valves which are especially adapted for repetitively operating at the extreme pressure differentials typically experienced in well bores.

1U nitenl fitter tell Inventor Appl. No.

Filed Patented Assignee lllnrold J. Urhnnonlty ll-llonston, Ten.

June 10, 1970 Dec. 21, 1971 Schlnmherner Technollony Corporntlnn New lforlt, 19X.

Originnl applicntion llltee. 112, 1969, fier. hi6. 1166531, now llntent No. 3,565,170, tinted l eh. 23, 1971. Divided rind thin nppllicntion June 10, 1970, Star. hlo. 41 1,9511

(3 0191111011, VALVES 11 0M WlElLlL 711111 01115 6 Clnims, 6 Drawing Winn.

llnt. 1C1 131611 5/1 1 Field 011 Search 166/ 100,

[56] llletercnccn Cited UNITED STATES PATENTS 3,107,730 10/1963 Lebourg 251/63 X 2,634,751 4/1953 Borer 251/614 X 3,514,074 5/1970 Self 251/205 X 2,243,711 5/1941 Lamb 251/63 X 2,584,890 2/1952 Leonard 251/61411 3,317,181 5/1967 Robbins 251/77 )1 3,397,717 8/1968 Tenltltu et a1 251/7711 Primary Examiner-Henry T. lilinknieit Anomcys-Ernest 1R. Archnmbeau, Jr, David L. Moseley,

William R. Sherman and Stewart F. Moore AllhS'llllRhC'll: The invention disclosed herein is directed to new and improved control valves which are particularly adapted for selectively operating pressure-actuated well tools. in particular, different embodiments are disclosed 01 highpressure control valves which are especially adapted for repetitively operating at the extreme: pressure differentials typically experienced in well bores.

CONTROL VALVES 1 01s WELL TU DLS This application is a division of U.S. Pat. No. 3,565,170, issued Feb. 23, 1971.

In conducting various well completion and testing operations, certain well tools are selectively operated from the surface by controlling the flow of high-pressure fluids such as a hydraulic fluid in the tool or the well bore fluids exterior of the tool. Typical of such tools are those disclosed in the Brieger U.S. Pat. No. 2,965,176 and the Whitten U.S. Pat. No. 3,385,364 for obtaining fluid samples from earth formations. With these tools, selectively operable valves are sequentially opened upon command from the surface for controlling either hydraulic fluids or well bore fluids to operate the apparatus. Since tools of this nature are operated only once during a single trip into a well bore, so-called break valves" have usually been used heretofore to control the flow of fluids under high pressure from one passage to another. These break valves are generally comprised of a frangible member blocking a fluid passage that is cooperatively arranged to fail upon being struck by an explosively impelled hammer. On the other hand, where a well completion tool is to be repetitively operated, the control valves employed therewith (as shown for example at 61 in the Urbanosky U.S. Pat. No. 3,430,698) have typically been operated by solenoid actuators. Hereagain, although such solenoid-actuated valves are generally reliable, valves of this type require a separate electrical conductor in the suspension cable as well as a significant power consumption for satisfactory operation. Moreover, since these solenoid valves must control fluids at extreme pressure differentials, the flow passages therein must be correspondingly small to limit the physical dimensions of the solenoid coils to reasonable sizes.

Accordingly, it is an object of the present invention to provide new and improved control valves which are particularly adapted for use with well tools having pressure-actuated ele ments that are to be selectively operated from the surface with a minimum number of electrical conductors and little or no added power consumption.

It is a further object of the present invention to provide new and improved selectively actuated control valves that are especially adapted to be repetitively opened and closed against the extreme pressures and fluid conditions normally encountered in a well bore without risking failure under these extreme operating conditions.

These and other objects of the present invention are pro vided by providing new and improved selectively actuated valves in which the valve member is movable between a closed position where the valve member is sealingly received within a stationary first valve seat and an open position where the valve member is received within a second valve seat cooperatively arranged to provide a progressively increasing flow area without the sealing member on the valve member ever being unsupported as the valve member is moving between its respective operating positions.

The novel features of the present invention are set forth with particularity in the appended claims. The invention, together with further objects and advantages thereof, may be best understood by way of the following description of exemplary apparatus employing the principles of the invention as illustrated in the accompanying drawings, in which:

FIG. 1 shows a well tool including a wall-engaging member that is selectively operated by control apparatus including a valve of the present invention as this tool will appear in a well bore;

FIG. 2 is a diagrammatic representation of a tool-anchoring system having control apparatus employing a valve arranged in accordance with the present invention;

FIG. 3 is across-sectional view of a portion of the tool of FIG. 1 to illustrate a preferred embodiment of a valve arranged in accordance with the present invention;

FIG. 1 is an enlarged view ofa portion of FIG. 3 but showing the valve in its fully opened position;

FIG. 5 is a further enlarged view of another portion of the valve depicted in FIGS. 3 and A; and

FIG. 6 is a cross-sectional view similar to that of FIG. 3, but showing an alternate embodiment of a valve also employing the principles of the present invention.

Turning now to FIG. 1, a well completion tool 10 is shown as it will appear when suspended in a borehole 11 from a suspension member such as a cable 12 having one or more electrical conductors (not shown in FIG. 1). As will subsequently be described in relation to the present invention, the tool includes control apparatus 13 having an extendible wallengaging anchor Ml which, when extended against one wall of the borehole 11, will urge the forward face of the tool housing 15 against the opposite wall of the borehole and secure the tool 10 in position for operation.

Since the tool 10 couldjust as well be any typical open-hole or cased-hole tool employing one or more extendible wall-engaging members, as at 1 1, only a brief description of the tool itself is required to illustrate a typical application of the new and improved valves of the present invention. Accordingly, the tool 10 depicted is the core-sampling tool fully described in the Urbanosky U.S. Pat. No. 3,430,716 for obtaining one or more elongated formation samples from selected earth formations traversed by the borehole 11. To accomplish this, the tool 10 includes suitably arranged motive means (not shown) for supporting and driving a pair of similar circular cutting wheels 16 operatively arranged for simultaneous rotation in outwardly converging vertical planes. Means (not shown) are provided in the tool 10 for carrying the cutting wheels 16 upwardly and, as they first move upwardly, extending the rotat ing wheels through an elongated opening 17 along the forward face of the tool housing 15 to begin cutting their way into the adjacent earth formation 13. Then, upon further upward travel of the cutting wheels 16, an elongated prismatic formation sample 19 will be cut out of the wall of the borehole 11. As the cutting wheels 16 approach the upper limit of their travel, they are retracted and then subsequently returned to their initial position near the bottom of the housing opening 17. Once the formation sample 19 is freed, the sample will fall through the housing opening 17 and be collected in the lowermost portion of the housing 15. Additional samples, as at 19, can be successively obtained by retracting the anchoring member 141, repositioning the tool 10 at different locations in the borehole 11, and reextending the wall-engaging member.

Turning now to FIG. 2, a schematic representation is shown of the control apparatus 13 which includes a fluid reservoir 20 that is conveniently located in the upper portion of the housing 15. For reasons that will subsequently be explained, the tool housing 15 is divided into upward and lower sections 21 and 22 that are telescopically fitted together and fluidly sealed in relation to one another by one or more sealing members 23 to normally close the upper end of the reservoir 20. The lower end of the reservoir 20 is closed by a transverse wall 26 across the housing section 22. A suitable pressure fluid, such as a typical hydraulic oil or the lilte, is introduced through one or more normally closed filling ports (not shown) in the housing 15 until the reservoir 20 is filled.

The wall-engaging member M is preferably mounted in an upright position outside of the housing 15 and coupled to the free end of one or more reduced-diameter axial rods 25 projecting forwardly from enlarged-diameter piston members 26 that are complementally received in lateral bores 27 formed at convenient locations in the housing. The piston rods 25 are extended forwardly through the side of the housing 15 and fluidly sealed in relation thereto by sealing members 211. Similarly, the enlarged piston members 26 are fluidly sealed by sealing members 29 to the walls of the lateral bores 27 to define therein separate enclosed chambers 30 and 31 ahead of and behind the pistons.

Pressure-developing means, such as a typical gear pump 32 driven by a reversible electric motor 33, are mounted in the housing 15 and preferably located within the fluid reservoir 20 itself. Since the pump 32 can be selectively driven in alternate directions (as indicated by the arrows 3A and 35), typical check valves 36 and 37 are connected to the fluid lines 321 and 39 on each side of the gear pump and respectively arranged to open only to admit fluid from the reservoir 20 to their associated fluid line. Thus, whenever the pump 32 is operating, only one or the other of the check valves 36 and 37 will be open to admit fluid from the reservoir 20 to either the conduit 38 or the conduit 39 depending, of course, upon which direction (34 or 35) the motor 33 is running.

Accordingly, when the pump 32 is being rotatively driven in the direction indicated by the arrows 34, the conduit 39 will be connected to what is then the suction side of the pump and the. check valve 37 will be open to admit fluid from the reservoir 20 through the conduit 39 to the pump. The other conduit 38 will, therefore, then be on the discharge side of the pump 32 and the check valve 36 will remain closed. On the other hand, when the pump 32 is running in the opposite rotational direction 35, it will take suction through the now-open check valve 36 and the conduit 38. The check valve 37 will now be closed, however, since the conduit 39 is then on the high-pressure or discharge side of the pump 32.

The other end of the conduit 39 and its associated connection to the pump 32 are connected by a conduit 40.to the enclosed chambers 30 ahead of the enlarged pistons 26. Thus, whenever the pump 32 is being driven in the direction shown by the arrows 35, fluid will be taken from the reservoir 20 through the check valve 36 and delivered under pressure by way of the conduit 40 to the forward piston chambers 30. This will, ofcourse, retract the wall-engaging member 14.

The other conduit 38 and its associated connection to the pump 32 are connected, by a conduit 41 and to the rearward piston chambers 31 preferably by the normally open and common ports of a three-way valve 42 connected in the conduit 41 for reasons that will be subsequently explained. A check valve 43 in the conduit 41 is arranged to permit flow from the pump 32 to the piston chambers 31 by way of the three-way valve 42 but halt flow in the reverse direction back to the pump. As indicated diagrammatically by the unbroken line 44, the threeway valve 42 is arranged to normally permit flow through the conduit 41 to the enclosed piston chambers 31 behind the enlarged pistons 26. Thus, so long as the three-way valve 42 is in its normal operating position shown in FIG. 2, whenever the pump 32 is driven in the direction shown by the arrows 34, fluid will be taken from the reservoir 20 through the check valve 37 and delivered under pressure through the conduit 41 and the three-way valve to the rearward piston chambers 31. This will, of course, be effective to forcibly extend the wall-engaging member 14.

It will be appreciated, of course, that steps should be taken to accommodate volumetric changes in the fluid reservoir 20 due to temperature variations as well as to maintain the reservoir fluid at the same pressure as that of the fluids in the borehole 11. Accordingly, the housing is preferably ar ranged to provide a supply reservoir 45 between spaced transverse walls 46 and 47 below the transverse wall 24. A piston member 48 is slidably disposed in the enclosed space 45 and fluidly sealed therein by a sealing member 49. A port 50 is arranged in the wall of the housing 15 to admit borehole fluids below the piston 48 and, since the reservoir 45 above the piston is filled with the hydraulic fluid, the hydraulic fluid in the supply reservoir is maintained at the borehole pressure. In the preferred manner of providing fluid communication between the space 45 and the fluid reservoir 20, a tubular member 51 is extended along the longitudinal axis of the housing 15 through the spaced transverse walls 24, 46 and 47 and fluidly sealed to each of these walls. One or more lateral ports 52 are provided in the tubular member 51 to allow hydraulic fluid to flow therethrough between the supply reservoir 45 and the fluid reservoir 20. The piston member 48 is, therefore, made annular and is free to move relative to the fixed tubular member 51, with a fluid seal 53 therebetween fluidly sealing the members to one another. As a matter of convenience, the conductors of an electrical cable 54 are brought into the reservoir through suitable conductor seals, as at 55, and passed through the tubular member 51 to various electrical components (not shown) in the lower portions of the tool l0.

Turning now to the operation of the control apparatus 13. The wall-engaging member 14 is, of course, preferably retracted while the tool 10 is being moved to a desired location in the borehole 10. Once it is determined that the wall-engaging member 14 is to be extended, by means of typical circuitry (not shown) at the surface as well as in the tool 10, a suitable source of electrical power (not shown) is connected to the motor 33 by its conductors 33a to drive the pump 32 in the direction indicated by the arrows 34. As the pump 32 is driven in this direction, fluid will be drawn to the pump from both the forward piston chambers 30 and, by way of the check valve 37, from the fluid reservoir 20 as well. The combined fluids will then be pumped on through the conduit 41 and the three-way valve 42 (by way of the normally open path 44 therethrough) into the piston chambers 31 behind the enlarged pistons 26. This will, of course, be effective to move the wall-engaging member 14 outwardly to its extended position.

Once the wall-engaging member 14 has contacted one wall of the borehole l1 and, as a result, moved the forward face of the tool 10 against the opposite borehole wall (as shown in FIG. 1), continued operation of the pump 32 will, of course, begin increasing the pressure in the rearward piston chambers 31. Since this pressure will continue to increase, means, such as a typical pressure switch 56 connected to the conduit 41, are provided for stopping the pump motor 33 once the pressure in the piston chambers 31 reach a magnitude sufficient to hold the wall-engaging member 14 against the wall of the borehole 11 with a desired force. Thus, by means of the pressure switch 56, the pump 32 will be halted once the pressure in the piston chambers 31 reach the predetermined cutoff setting of the pressure switch. Ordinarily, the pressure in the piston chambers 31 will remain relatively constant once the pump 32 is halted. Should, however, there be leakage of some nature or should the wall-engaging member 14 move further outwardly into, for example, a soft place in the formation 18, the pressure in the piston chambers 31 will decrease. Thus, to maintain the pressure in the piston chambers 31 within a desired range, the pressure switch 56 is also suitably arranged to restart the pump 32 should the pressure in the rearward piston chambers drop below a predetermined pressure. These settings for the pressure switch 56 will, or course, be selected to keep the pressure in the piston chambers 31 at a level calculated to maintain the tool 10 anchored with at least a force sufficient to reliably hold it in position in the borehole 11.

To retract the wall-engaging member 14, the pump 32 is driven in the direction indicated by arrows 35. Simultaneously with the starting of the motor 33, the control apparatus 13 further includes a new and improved pressure-actuated valve 57 arranged in accordance with the principles of the present invention and connected to the conduit 41. As will subsequently be explained in detail, the valve 57 is opened to enable fluid in the rearward piston chambers 31 to be drained (by way of the conduit 41 and the valve 42) back to the fluid reservoir 20. The check valve 43 will, of course, prevent this fluid from returning by way of the pump 32. As fluid is forced from the enclosed piston chambers 31, the pump 32 will be simultaneously removing fluid from the fluid reservoir 20 by way of the check valve 36 and pumping it into the forward piston chambers 30 to retract the wall-engaging member 14. Once the wall-engaging member 14 is fully retracted, the pump motor 33 will be stopped and the valve 57 will be reclosed in response to the decrease in pressure. The control apparatus 13 is then again in readiness for repeating the above-described operations. It will be recognized, of course, that any volumetric changes in the reservoir 20 during these operations will be accommodated by movement of the piston 48 within the supply reservoir 45.

The above-described operations will ordinarily be sufl'icient for typical service of the anchoring apparatus 13. It will be appreciated, however, that malfunctions can occur in even the best of well tools. Accordingly, to insure that the wall-engaging member 14 can always be retracted should any portion of the control apparatus 13 fail while the tool 10 is anchored, the hydraulic system is adapted to be disabled in response to movement of the suspension cable 112. To accomplish this, an annular piston member Ed is slidably disposed in an annular chamber 59 formed in the housing l between the partitions 2d and id around the tubular member 5i and fluidly sealed therein by sealing members 60 and nil. The piston is initially positioned at the upper end of the chamber 59 and held there by the friction of the sealing members an and will. A conduit n2 is connected between the chamber 59 above the piston 5t! to the normally closed port of the three-way valve d2. An access port in the housing is provided to provide communi cation into the chamber 59, with a suitable closure member 63 normally closing the port.

in the usual case, the three-way valve 42 will remain closed and block communication to the chamber 59 which is initially empty and at atmospheric pressure. It will be appreciated, however, that once the three-way valve d2 is shifted to open flow (as shown by the diagrammatic flow path 64) between the common port and normally closed port of the three-way valve, direct communication is established (by way of the conduits M and 62) between the rearward piston chambers 3t and the empty chamber 59. Thus, actuation of the three-way valve M will be effective to drain the hydraulic fluid in the rearward piston chambers 3i into the empty chamber 59 and reduce the pressure in these piston chambers sufficiently to retract the wall-engaging member M. To actuate the threeway valve M, an actuating member 65 is connected between the valve and the lower end ofthe upper housing section 2ll. it will be appreciated, of course, that the telescoping arrange ment of the adjacent ends of the housing sections 2ll and 22 will permit one to move relative to the other within the limits provided by an outwardly directed shoulder 66 on the lower end of the upper housing section and spaced below an inwardly directed shoulder 67 on the lower housing section.

Accordingly, should there be a malfunction in the hydraulic system of the control apparatus 13 while the tool ill] is anchored as shown in FIG. 1, the suspension cable 112 will be tensioned sufficiently to fail one or more shear members, as at 68, which ordinarily secure the housing sections 21 and 22 to one another. Once the shear member #68 fails, the upper housing section 21 will be free to move upwardly in relation to the anchored housing section 22 until the shoulders tin and 67 engage. This upward movement will be sufficient to act through the actuating member 65 and shift the three-way valve d2 to its other position to open communication (by way of the path b ll) between the piston chambers Bill and the empty chamber 59. It should be noted that the sealing members 23 will lteep the fluid reservoir still sealed. Once the control apparatus 13 has been disabled in this manner, it is, of course, necessary to return the tool It) to the surface.

From the foregoing description of the control apparatus 113 it will be appreciated that the new and improved control valve 57 is especially arranged to remain closed so long as the pump 32 is either not operating or is being driven (in the direction of the arrows M) to extend the wall-engaging member id. 0n the other hand, the control valve 57 of the present invention is adapted to open in response to the pressure developed when the pump 32 is driven in the opposite rotative direction Zlfi for retracting the anchor member 14. ln this manner, by arranging the new and improved control valve 57 to operate only in response to selected operations of the pump 32, the previous practice of employing one or more solenoid-actuated valves is not required with the control apparatus 113.

Accordingly, as best seen in Fig. 3, in a preferred embodiment of the control valve 57, the valve is preferably disposed in a lateral bore 69 arranged in the tool housing l5 and joining an enlarged diameter axially aligned bore 70. So that access may be conveniently gained to the valve 57, the lateral bores 69 and 70 are extended transversely across the housing l5 and fluidly sealed at their respective open outer ends by suitable closure members such as threaded end caps or plugs 71 and 72. Fluid passages 73-75 are suitably formed in the tool housing 15 and terminated at longitudinally spaced intervals along the combined length of the lateral bores 69 and 70. As will subsequently be explained, the first: passage 72 terminates near the left-hand end (as viewed in FIG. El) of the smaller lateral bore t5) and serves as at least a portion of the pressureactuating conduit "/6 schematically represented in lFlG. 2, the second passage 74* (which serves as at least a part of the conduit dl) is terminated near the inner end ofthe smaller lateral bore, and the third passage 75 provides communication between the enlarged'diameter lateral bore 7t) and the fluid reservoir 20.

The control valve 57 includes an elongated spool member 7? that is slidably disposed in the smaller lateral bore W and has enlarged-diameter end portions 7-ll and 79 on its opposite ends fluidly sealed therein which respectively serve as a piston actuator and a valve member. As illustrated in lFlG. 3, the spool member 77 is arranged to normally position the piston actuator 7b a short distance inwardly from the intersection of the first passage 73 with the smaller lateral bore 0W so that, upon an increase of fluid pressure in the first passage, the spool member will be shifted further inwardly (to the right as viewed in the drawings) against biasing means such as a compression spring dtl arranged in the smaller lateral bore and engaged between the enlarged head Iii and an inwardly directed shoulder hll formed near the right-hand end of the smaller bore. if additional biasing force is required, a second compression spring 82 can also be arranged in the enlarged bore '70 between the head of the valve member "/9 and the right-hand closure member 72. it will, of course, be appreciated that the springs 80 and 82 will be effective to return the spool member 77 to its initial or closed position upon a decrease of pressure in the fluid passage 73.

in the preferred embodiment of the control valve 57 illustrated in FllG. 3, the right-hand closure: member 72 is provided with a coaxial extension 83 having one or more lateral openings M, with the extension projecting inwardly into the enlarged bore 7% and terminating immediately adjacent to the shoulder 35 defined by the junction of the enlarged bore and the lateral bore 619 to the right of the shoulder till. A blind coaxial bore lid is formed in the inwardly projecting extension ti?! and, for reasons that will be subsequently explained, receives a plurality of coaxial rings or sleeves s'i-ns that are tandemly disposed in the blind bore between the shoulder 5% and the closed outer end of the closure member "72. Biasing means such as a stout compression spring or one or more tandemly disposed Bellville washers htl are arranged in the blind bore do for urging the stacked sleeves tikbh inwardly against one another and the opposed outwardly facing shoulder hfi.

Of particular significance to the present invention, it will be noted that the internal diameterof the several stacked sleeves lii-W is equal to that of at least that portion Elll of the smaller lateral bore 69 between the shoulders lllll and d5. Thus, as depicted in FIG. 3, so long as the spool member '77 is in its illus trated position, the enlarged valve member 79 will be received in the inward terminal portion @l of the lateral bore b9 and a sealing member 92 around the valve member will be seated therein to block fluid communication between the passages 74 and 75 Similarly, by virtue of a sealing member 93 around the piston member 78, fluid communication will always be blocked between the passages 73 and 7d.

Accordingly, upon movement of the spool member 77 forwardly toward the right-hand closure member 72, the enlarged valve member 79 will be moved. from the fixed seat E l into successive seating engagement within the several coaxial sleeves 87-h9 as the spool is progressively moved outwardly to the right. To limit the forward travel of the spool member 77 into the coaxial sleeves 37-bi stop means are provided such as a post Wl that is disposed against the outer end of the closure member 72 and extended inwardly therefrom into the blind bore 86 to a position calculated to halt the valve member 79 where its sealing member @2 will be engaged with the outermost or right-hand sleeve when the spool has reached its intended extended or forward position.

As best seen in lFlGSl. 4 and 5, the coaxial sleeves tl7-d9 are particularly arranged to maintain their opposed ends slightly separated from one another so as to provide a controlled fluid communication path between the passages 74 and 75 when the valve member 79 is not seated within the fixed valve seat 91. In the preferred manner of maintaining the sleeves 87-89 slightly spaced apart, two or more longitudinal projections, as at 95, 96 and 97, of a very minor height are respectively formed on one end of each of the sleeves andadapted to engage the adjacent end of the next sleeve or the shoulder 85. In this manner, substantially continuous circumferential gaps 98-100 will be defined between the shoulder 85 and the opposed ends of the several rings 87-89. Although the longitudinal spacing of these gaps 98-100 need only be in the order of 0.0001 to 0.005 inch, at the extreme operating pressures normally imposed on the control apparatus 13 sufficient flow rates will be obtained between the passages 74 and 75 to achieve satisfactory operation. It should be noted that the gaps 98-100 need not be equal. ln fact, it is preferred that the first gap 98 be much smaller than the other gaps 99 and 100; and, that the last gap be the larger of the three gaps.

Accordingly, of particular significance to the present invention, it will be appreciated that as the valve member 79 is moving between either of its two positions respectively depicted in FIGS. 3 and 4, the sealing member 92 thereon will always be confined within one or more of the several sleeves 87-89 so as to effectively support the sealing member against deformation or extrusion by the extreme fluid pressures acting across the sealing member as the valve member opens. Furthermore, the sealing member 92 will be fully supported within the outermost sleeve 89 when the valve member 79 is open and also will be supported within the fixed valve seat 91 when the valve member is in its closed position. Accordingly, at no time during the repetitive operation of the control valve 57 will there be a chance that the sealing member 92'will be damaged by the flow of high-pressure fluids between the passages 74 and 75.

It will be appreciated, of course, that the control valve 57 is best suited for controlling the flow of relatively clean hydraulic fluids in view of the narrowness of the gaps 98-100. Accordingly, an alternate embodiment is depicted in FIG. 6 of a control valve 57 arranged in accordance with the principles of the present invention that is particularly adapted for controlling the flow of dirty fluids such as well bore or formation fluids. As seen there, the control valve 57 is substantially arranged as the control valve 57 but with the exception that only a single sleeve 89 is disposed in the enlarged bore 70' and adapted to be moved to the right (as viewed in FIG. 6) against the biasing spring 82' as the valve is openedagainst the biasing spring 80'. Thus, as the valve member 79' is moved toward its open position, once the sealing member 92' thereon is received within the coaxial sleeve 89, further movement of the spool 77 will progressively open the circumferential gap between the rear of the sleeve and the forwardly facing shoulder 85 This progressive opening of this circumferential gap will, of course, accommodate a correspondingly greater flow of fluids between the passages 74 and 75' without endangering the integrity of the seal 92' which is, by this time, safely supported within the movable valve seat or coaxial sleeve 89'. Closure of the valve 57 can, of course, be readily accomplished by simply reducing the pressure in the passage 73 so that the springs 80 and 82' will return the valve spool 77 to its initial position.

Accordingly, it will be appreciated that the present invention has provided new and improved control valves for use in well tools having selectively controlled fluid systems. By virtue of the particular design of the new and improved disclosed valves of the present invention, by providing spaced valve seats for supporting the sealing member of the moving valve member as it moves between its open and closed positions, potential damage to the sealing member will be eliminated to permit reliable repetitive operation of the control apparatus of the present invention.

While particular embodiments of the present invention have been shown and described, it is ap arent that changes and modifications may be made without epartmg from this invention in its broader aspects; and, therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of this invention.

What is claimed is:

l. A valve comprising: a valve body having first and second axially aligned adjoining bores and first and second fluid passages in fluid communication with said adjoining bores respectively; a cylindrical valve member having an annular sealing member mounted therearound operatively disposed in said valve body for axial movement therein between said adjoining bores; pressure-responsive actuating means operatively arranged on said body for selectively moving said valve member between said adjoining bores; first means in said first bore defining an annular valve seat therein adapted for coaxially receiving said sealing member and operative for blocking fluid communication between said fluid passages upon movement of said valve member into'said first bore to bring said sealing member into sealing reception within said valve seat; and second means in said second bore operative upon movement of said valve member into said second bore for continuously supporting said sealing member and progressively increasing fluid communication between said fluid passages in proportion to the extent of said valve member into said second bore, said second means including a plurality of stacked rings having axial bores of equal diameters defining supporting surfaces and tandemly disposed in said second bore in coincidental alignment with said valve seat for coaxially receiving said valve member and supporting said sealing member on said supporting surfaces as said valve member moves into said second bore, said rings being respectively shaped to provide axially spaced gaps between their ends for defining an increased flow area between said fluid passages as said valve member is advanced further into said second bore, and spring biasing means operatively arranged between said valve body and said rings for urging said rings toward said first bore and adapted, upon movement of said valve member into said second bore, to yield so that said axially spaced gaps between said rings will progressively increase in proportion to the distance over which said valve member is moved into said second bore.

2. The valve of claim 1 wherein said valve seat is defined by the walls of said first bore.

3. The valve of claim 1 further including stop means operatively arranged on said valve body for limiting the maximum distance over which said valve member can be moved into said second bore.

4. The valve of claim 1 wherein said pressure-repsonsive actuating means include a third bore in said body axially aligned with said first and second bores, a piston member operatively disposed in said valve body for axial movement in said third bore, a third fluid passage in said valve body in fluid communication with said third bore, and means operatively interconnecting said piston member and said valve member whereby, upon application of fluid pressure to said third fluid passage, said piston member will move said valve member from one of said first and second bores to the other of said first and second bores.

5. The valve of claim 4 further including biasing means operatively arranged between said valve body and said piston member for moving said valve member from said other bore to said onebore upon removal of fluid pressure from said third fluid passage.

6. The valve of claim 1 wherein each of said rings have end projections adapted for maintaining said rings slightly spaced to provide said axially spaced gaps. 

1. A vAlve comprising: a valve body having first and second axially aligned adjoining bores and first and second fluid passages in fluid communication with said adjoining bores respectively; a cylindrical valve member having an annular sealing member mounted therearound operatively disposed in said valve body for axial movement therein between said adjoining bores; pressure-responsive actuating means operatively arranged on said body for selectively moving said valve member between said adjoining bores; first means in said first bore defining an annular valve seat therein adapted for coaxially receiving said sealing member and operative for blocking fluid communication between said fluid passages upon movement of said valve member into said first bore to bring said sealing member into sealing reception within said valve seat; and second means in said second bore operative upon movement of said valve member into said second bore for continuously supporting said sealing member and progressively increasing fluid communication between said fluid passages in proportion to the extent of said valve member into said second bore, said second means including a plurality of stacked rings having axial bores of equal diameters defining supporting surfaces and tandemly disposed in said second bore in coincidental alignment with said valve seat for coaxially receiving said valve member and supporting said sealing member on said supporting surfaces as said valve member moves into said second bore, said rings being respectively shaped to provide axially spaced gaps between their ends for defining an increased flow area between said fluid passages as said valve member is advanced further into said second bore, and spring biasing means operatively arranged between said valve body and said rings for urging said rings toward said first bore and adapted, upon movement of said valve member into said second bore, to yield so that said axially spaced gaps between said rings will progressively increase in proportion to the distance over which said valve member is moved into said second bore.
 2. The valve of claim 1 wherein said valve seat is defined by the walls of said first bore.
 3. The valve of claim 1 further including stop means operatively arranged on said valve body for limiting the maximum distance over which said valve member can be moved into said second bore.
 4. The valve of claim 1 wherein said pressure-repsonsive actuating means include a third bore in said body axially aligned with said first and second bores, a piston member operatively disposed in said valve body for axial movement in said third bore, a third fluid passage in said valve body in fluid communication with said third bore, and means operatively interconnecting said piston member and said valve member whereby, upon application of fluid pressure to said third fluid passage, said piston member will move said valve member from one of said first and second bores to the other of said first and second bores.
 5. The valve of claim 4 further including biasing means operatively arranged between said valve body and said piston member for moving said valve member from said other bore to said one bore upon removal of fluid pressure from said third fluid passage.
 6. The valve of claim 1 wherein each of said rings have end projections adapted for maintaining said rings slightly spaced to provide said axially spaced gaps. 